Grinding machine



Feb. 3, 1931. V 5 c s 1,791,442

GRINDING MACHINE Filed April 14; 1926 5 Sheets-Sheet l I IE-FM W IM'SMT 61mm; I

Feb. 3, 1931. J. E. CASTER 1,791,442

GRINDING MACQINE 5 Sheets-She'et 2 Filed April 14, 1926 J. E. CASTER GRINDING MACHINE Feb. 3, 1931.

Filed April 14, 1926 5 Sheets-Sheet 3 w H ma Fens, 1931-.

J. CASTER GRINDING MACHINE Fil ed April 14, 1926 5 Sheets-Sheet 4 Feb. 3, 1931. J. E. cAsTER 2 GRINDING MACHINE I Filed April '1926 5 Sheets-Sheet 5 Patented F eb; 3, 1931 warren STATES I PATENT OFFICE JOHN E. CASTER, OF CINCINNATI, OHIO, 'ASSIGNOR, BY MESNE ASSIGNMENTS, T0 GIN- CINNATI GRINDERS INCORPORATED, OF CINCINNATI, OHIO, A CORPORATION OF OHIO GRINDING Application filed April 14,

This invention relates to improvements in a novel apparatus for the production of articles of circular form in cross-section, having a predetermined final axis.

Priorto the present invention it has been customary to produce articles of this type on what is known as a center grinding machine, in which the article is supported by the two rigidly fixed centers and the work and wheel given a relative feeding movement, one toward the other. ,Vith articles of any appreciable length, it has been custo mary to use a steady rest or member backing up the work, to eliminate the variations due to spring of the work or yielding of the centers during grinding. These operations however, have not been entirely satisfactory, particularly in the case of work. which is initially out of round, or in which the centers are not concentrically located, 'due to the fact that during the grinding of such articles the grinding wheel would strike the work only intermittently or with a chopping action and in addition, due to the fact that with such work it is impossible to so adjust the steady rest memher as to continuously engage and support the work prior to the rounding up thereof.

It is, therefore, one of the objects of the present invention to provide a novel method of producing work-pieces of this character which shall make it possible to do away with the individual dogging of the workpieces, by providing a different manner of securing their rotation, said method consisting primarily in supportingthe work-pieces on centers, one or both of which is mounted for a lateral or vertical yielding or floating action and in providing a backing member which shall positively engage the work during the entire gotation thereof, and itself produce the pressure of the work against thagrinding-wheel, in place of depending upon the centers for applying the work pressure.

A. further object of the invention is the provision of a novel and improved mechanism for adaptation of a centerless grinder to enable the same to be employed for production or workpieces-ground to a prede- MACHINE 1926. Serial No. 102,067.

termined axis and accurate as to diameter within, the finest commercial limits.

' A further object of the present invention /in the normal operation of either of said mechanisms.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification taken in connection with the accompanying drawings, forming a part thereof, and it will be understood that any modifications in the specific details of construction hereinafter illustrated may be made within the scope of the appended claims, without departing from or exceeding the spirit of the present invention.

Figure 1 represents a side elevation of a machine, embodying the present improve ments.

Figure 2 represents a fragmentary transverse sectional view thereof, taken as on the line 2-2 of Figure 1.

Figure 3 represents a plan view of the work-supportin and engaging members, parts being bro en away.

Figure 4 is a vertical sectional view on line 4-4 of Figure 3. v

Figure 5 is a diagrammatic view illustrating the manner in which the stock is removed from the work-piece.

Figure 6 is a diagrammatic view illustrating the general operation of the machine on the work.

Figure 7 is a diagrammatic view particularly illustrating the manner of limitation of size of the work-piece.

Figure 8 is a plan view of a slightly modidle therefor.

Figure 12 is a similar view, illustrating the work as supported for longitudinal movement during grinding.

Figure 13 is a semi-diagrammaticvertical sectional View illustrating an adjustable work-rest member in position to properly engage a work-piece of large diameter.

Figure 14is a similar view illustrating the adjustment of the work-rest for engagement with a small diameter work-piece.

Figure 15 is a sectional view illustrating the means for holding the floating spindle against movement as when setting up the machine for example.

In the drawings in which similar characters of reference are einployed to denote corresponding parts throughout the several views, A'des'ignates the bed of a grinding machine, having suitably journaled thereon the grinding wheel B, operable at a high or grinding rate of speed and moving in a clockwise direction, "as viewed in Figure 1, while opposing said wheel B is a regulating wheel C, supported on a slide D, for movement toward and awe from the grinding wheel. This wheel is a so driven in a clock-wise direction at a slow rate of speed for re ulating the rate of rotation of the work, t e operative surfaces of the two Wheels therefore at their adjacent point movin in oppositedirections. Risin from the bed intermediate these wheels is t e bracket E, supporting the angle top work-rest blade 10. This bracket also supports the, floating headstock spindle 11, havin a ball-end 12', swivelled in socket 13 of adjustable slide block 14. This block is movable in bore 15 of bracket 16, being locked against rotation b screw 17 engaged in the key-way .18 and eing inwardly ad justed by screw 19. A pin 20 projecting from the sides of-ball-end, riding in the elongated slots 20'- of/block 14, prevents rotation of spindle 11, but permits a free action of ball a socket. 1 3

' To control the position of this spindle, a second or supplemental bracket portion 21 isprovided, having a passage 22 of'size to receive the inner end of the spindle 11, with a suitable clearance permittinglimiteduniversal oscillatory movement of the spindle. This bracket is further provided with the spring friction device 23, bearin against the end-0f the spindle to prevent t e atin wheel from lifting. the work from te' bla ewhen the 'rinding wheel is not in contactjwith as viewed in Figure 1, while mounted on the bracket E at the near side'of the machine is the tail'stock spindle casing 24, within which and is allowed to find or establish its own center,

provided for limiting the final thus limiting the I established axis.

It is. to be noted that .the arts dust 'd'g a two diameter work-piece, asfor example,

the work-piece illustrated in Figures 2 and 3 of the drawings, having the larger diameter portion 27 which has been ground in a prior operation concentric with the centers by either center or centerless methods andhaving a second portion 28, which must be formed concentric or co-axial with the portion 27. In

the grindin of such work-pieces, there is provided a woik-rest portion 29 on bracket E, to engage the portion 27 and properly support it in the machinefi'henthe portion 28 is resting on the upper surface of the work-rest 10. Itis to be understood that the work-piece 2728 is provided with the customary centers adapted to receive the points of the head and tailstock spindles 11 and 25 respectively. The work-piece having been placed in engagement with the work-rest and supporting block, the tailstock spindle 25 is then brought in and the height of the work-rest and supporting block are such that the points of the spindles will automatically engage the centers, slight- 1y backing up or raising the piece but not sutiiciently to destroy contact between the members 10 and 28.

In grinding of work by the centerless method, the Work-piece is supported on a work rest between grinding and regulating wheels the diameter being determined by the final separation between rinding and.-regu-- lating wheels. In work oi the present nature, however, it is necessary that the axis of the ,work be determined by the position of the centers in its two ends. At the same time, it is desirable that the grinding action be as continuous as possible and the work satisfactorily backed up during the entire grinding operation. This presents a number of difiiult problems which have for the first time been solved by the present machine. The machine itwill be noted has at least one floating center or may have two, as shown in Figure 8 for example. In any event, it is necessary witha floating center that some means be a proach of a iisof the work to the grinding wheel,

final size of the work and insuring the work infcross-section being a circle .whose center dies on this previously" ".Inthe accomplishment of the this result, use 1s made of a suitable stop for '.the oscillating headstock spindle, this being shown in Figures 3 and 4 'for example, as produced by forming a flat at 30 on the spindle for engagement by the end of the micrometer-= adjusting screw 31, provided with graduations 32, coupled with the index finger 1s slldably supported the tailstock spindle 25,

33 to show the amount of adj ustment. AttenllU' angle is preferably substantially parallel to a tangent to the regulating wheel at the point not contact with a finished work-piece.

The action of the machine and the reason for this particular relationship oi the parts will probably be best understood by reference to Figures 5, 6 and 7 of the drawings. Figure 5 illustrates the actual operation of the machine in rounding up a piece of work which was initially eccentric to the predetermined axis. M indicates the original exterior of the work-piece shown as substantially a true circle, but true as respects a center or axial line N, and eccentric as respects the axial line 0, which is determined by the position at which'the two centers were placed in the ends of the work and about which therefore the final work-piece curve must be generated. The grinding is considered as starting at the point P, being produced by an inward feeding movement of regulating wheel C, pressing the Work against the grinding wheel. Q indicates the final size of work desired, being a circle generated about point 0 as a center. It is of course, to be understood that the dimensions here shown are greatly exaggerated to facilitate an understanding of the invention as in actual practise the 'total stock removal would probably not exceed 050. As the grinding starts at P and the regulating wheel 0 is given a uniform inward movement by suitable manual or automatic mechanism, the original grinding will be in the form of a uniform spiral path E. This grinding will continue and the shifting headstock center will move with the work .toward the grinding wheel until stop screw 31 engages the flat 30 .on said spindle. This limits the further movement of the spindle toward the grinding wheel and consequently limitsthe amount of stock which the grinding wheel can remove. The point at which this limitation occurs has been indicated as S. As the regulating wheel continues to rotate the Work and move inwardly, a differentspiral of stock removal will be produced. As S is practically zero, the stock removal at a diametrically opposite point or T, will be substantially double that of the initial spiral considering a constant movement of the regulating wheel. This will then continue in successive displaced spirals, as indicated, until the regulating wheel reaches its innermost position of movement, determining the final size of work-piece when the spirals will have merged into the final outline Q.

This limitation effect will probably be bet ter appreciated by reference to Figure 7, inv

which the stop, regulating wheel and work rest are diagrammatically indicated, these being the three points determining the final size and position of the work-piece; the point U being shown where the tangent to the regulating Wheel at the point of contact with the final work-piece is also tangent to the surface of the work; the point W being the point of contact of the surface of the work with the supporting work-rest and the point X being the point determined by engagement of the flat on the headstock spindle with the stop which may be considered as a concentric circle of the work-piece as indicated by the dotted line circle Y. The efiect is the same as though this were a second tangent or contacting member operating on the final surface of the work, corresponding to the dotted tangent X, parallel with the fiat- 30 of the headstock spindle.

It will thus be seen that the three contact members indicated in the diagram by U, X and W form a three point bearing, determining the position of the finished work-piece, while the grinding wheel is a fourth member, the other members being so adjusted relative to the grinding wheel that the grinding wheel will produce the desired circular outline Q, removing all points on the surface of the work exterior to circle Q, when the final position is determined as noted by being prevented by the three determinents from cutting into the work within said desired circle. It will be understood by those conversant with general grinding operations that after a work-piece has, been reduced to size and bnought up against a stop, if the grinding wheel and work-piece both continue to r0- tate for an appreciable period, there is a certain spring in the parts and general yieldability tending to produce a sparking out or final grinding and at the same time liable, if the relative rotation of the parts continues,

to cause a cutting below the exact predeter mined size, as established by the stop. This must be given particular consideration in connection with the present mechanism, in which a considerable amount of grinding has 'to be done on one side of the piece, while very little grinding is taking place on the opposite side. The present mechanism has therefore been designed to particularly take care of this point. In the center-less grinding operation the work-receiving throat for practic-a1 purposes may be considered as of V shape, that is to say, the grinding is done above the axial plane connecting the grinding and regulatingwheels, with the result that the wheels converge below the work and as v'orlc decreases.

sible for the stop to come into operation as indicated in Figure 5, limiting grinding ac-- tioned is disposed at an angle converging to-' ward or approaching the grinding wheel surface, so that there is both inward and downward movement as the diameter of the In this manner, it is pos tion 'on the side of shorter radius and then the combined action of downward dropping and inward sliding which produces, in other words, the effect of a receding stop device, allows limited amounts of material to be removed on the shorter radius for each maximum amount removed on the longer radius. As a result, the surface on the shorter radius each time receives a slight but proper amount of grinding action, preventing the formation of flats or indentations therein by the grinding wheel and insuring a more steady and uniform rotation of the work-piece, due to the fact that there is thus maintained a constant pressure between the work-piece, regulating wheel and grinding wheel, until the work has been reduced to its final finished form. This eliminates the irregular action of the grinding wheel, which is characteristic of truin'g up work of this nature in the stand;

- ard center grinding machines.

Of course, the same result here described could be attained by the use of a substantially straight stop member, together with means for causing it to variably recede during the grinding operation as is brought out for example in Figures 9 and 10. In Figure 9,

' there is shown a rock lever 34, pivoted to the bracket E and coupled with theregulating wheel slide 1) by a link 35, being so proportioned that the stop will move back a limited cause it to recede slightly toward the grind- 'in wheel during its inward movement. n this connection attention is also invited 1 to Figure 8 of the drawings, in which is amount in proportion to the inward movement of the regulating wheel.

In an alternative construction the grind ing wheel is shown as mounted on a slide 36,

movable toward the regulating wheel, in

which event an mm 34 pivoted to thebed, carries a sto device 37 for cooperation with the headstoc spindle and a link 35' couples this arm with the grinding wheel slide, to

shown the use of a pair of similar headstock spindles 11, one attach side of the machine,

' one of said spindles being mounted on a slide 38 for in and out movement to clamp the work in place. In this form it will be noted yboth spindles have the gyratory action in place of one bein rigidly mounted as in the previously descri d form of the invention, the o rationin both instances being otherwise identical. 7 Y I In the operation of a machine of this type it is merely necessary to lay the work-piece on the work-rest and in engagement with the guide block or blocks 29 and to relatively shift the two spindles, so that their points will engage the formed centers in the work, steadying and positioning the work. The grinding and regulating wheels are then caused to move one toward the other to operatively engage the work on opposite sides, the work being free to float back and forth between the wheels, but being limited as to its approach towards the grinding wheel, with the result that the circle Q, is the smallest circle which will contact with or be produced by the grindingwheel, as the work is rotated on its center by engagement of the regulating wheel therewith.

In Figure 11 the machine is shown as forming an intermediate work surface 40 on a gaging the previously formed co axial surface 42 in place of engaging th'e spindle. The operation in either instance however, is the same as has been brought outin connection with the dotted line circle Y of Figure 7 This is true since whether the stop engages a definite point on the spindle, a predetermined radius length from the desired axis 'or whether it engages a surface of rotation having the same radius, the limiting effect upon approach of the axis of work to the operative plane of the gringing wheel surface is the same.

*In Figure 12 a diflerent form of machine is illustrated to the extent that the brackets bearing the work centers are shown as carried by a slide 44, capable of transverse movement on the bed oiitlmnnachine, with the result that in this form of the invention a workpiece or section of greater length than the width of the grinding wheel may be operated upon, and the entire surface ground down in the same manner as previously described in .connection with a shorter WOIk-SQCtlOIl. The

-the like in which a floating center is employed, incombination with means for limitmg its movement in the direction of the grinding wheel and in which suitable means are employed for urging and holding thethe grinding wheel B,.as well as with the slide D for the regulating wheel C. This permits of in and out adjustment of either of the wheels relative the intermediate work-supporting centers such as 11.

In the production of work by the principles previously outlined, I have found it is desirable to have the work-rest contact with a radius of the work at a given and prescribed angle and that the work-rest should be maintained at this relative point of contact irrespective of the diameter of the work, in order that best grinding results may be obtained. This result however, is possible to a limited degree only, when the work is held between centers and the work-rest or blade has a vertical movement only, as is indicated in Figure 2.

As an alternative construction therefore, I slidably mount on the bed A the work-rest supporting bracket 47, hearing the work-engaging blade 48 designed to contact with work-pieces of varying sizes along the radius 49, making a predetermined angle, or as indicated, an angle of about 50 from the horizontal plane of the machine. The movement of the support 47 is accomplished by rotation of screw 50 and its angle of line of movement is parallel with radius 49, so that the blade 48 correspondingly contacts with and supports the work-piece in proper position relative to the fixed and floating center lines of the spindles 11 and 25, irrespective of the diameter of the work-piece to be ground.-

I have additionally found it advantageous in connection with a floating spindle structure such as described, in some instances, to be able to lock the spindle temporarily in a predetermined axial position alined with the opposed non-gyratory spindle. This is ac complished by forming an elongated containing block 14 for the ball 12', and spindle 11 with an extension 51, having a central axially drilled socket 52 at its rear end. This socket is adapted to be engaged by cone point 53 of locking screw 54 whichmay be carried as by the end ca 55 onthe supporting bracket 16 for the bloc 14'. Inward adjustment of this screw member will'caus'e its cone point to engage in the socket 52 and lock the spindle l1--51 into axial alinement with the screw as indicated, while partial or entire withdrawing of the screw will correspondingly release and .permit of renewed gyratory movement of the oscillating or floating spindle.

What is claimed is:

1. A grinding machine including opposed.

grindingand regulating wheels, a work-su .port pro ecting into the throat betweent e wheels, means for producing relative movement of the wheels to vary the width of the grinding throat and means for limitin the approach of the axes of the work an the grinding wheel.

2. A grinding machine including opposed grinding and regulating wheels and an intermediate work-support, a centering memher for engagement with one end of a workpiece, when on the support, a floating centering device i opposition to the first centering membe for engagement with the opposite end of the work and means for limiting the floating movement of said centering device.

3. A grinding machine including opposed grinding and regulating wheels and an intermediate work-support, a centering member for engagementwith one end of a work-piece, when on the support, a floating centering device in opposition to the first centering member for engagement with the opposite end of the work, means for limiting the floating movement of said centering device, said mean including an adjustable stop disposed at the grinding wheel side of the floating centering device.

4:. A grinding machine including opposed grinding and regulating wheels and an intermediate work-support having a surface for engagement with the periphery of a workpiece and additional means for terminally engaging the work-piece, one at least of said means being mounted for universal gyratory movement.

5. A grinding machine including opposed grinding and regulating wheels and an inter-f mediate work-support having a surface for engagement with the periphery of a workpiece, additional means for terminally engaging the work-piece, one at least of said means being mounted for universal gyratory movement, and means for restricting the general gyratory movement thereof.

6. A grinding machine including opposed grinding and regulating wheels and an intermediate work-support havinga surface I for engagement with the periphery of a workpiece, additional means for terminally engaging the work-piece, one at least of said means being mounted for universal gyratory movement, means for restricting the general gyratory movement thereof, and additional.

means for definitely .limiting movement of said member in the direction of the operative surface of the grinding wheel.

7. A grinding machine of the character described including opposed grinding and regulating wheels and an intermediate worksupport for engagement with the periphery of a work-piece, movable work-centering means for positioning the work on the sup port, and a receding stop member for-engagement with said means to limit the movement of the work-piece on the support. 7

v8. A machine of the character described, in-

cluding opposed grinding and regulating wheels and an intermediate work-support, and means for controlling the position of a work-piece on the support, including center-' ing spindles, one at least of said spindles being mounted for gyratorymovement about a point remote from its work-engaging end,

and one of said spindles being longitudinally movable relative to the other for insertion and removal of a work-piece.

9. A machine of the character described,'

including opposed grinding and regulating wheels and an intermediate work-support, and means for controlling the position of a work-piece on the support, including centering spindles, one at least of said spindles being mountedfor gyratory movement about a point remote from its work-engaging end, and .one of said spindles being longitudinally movable relative to the other for insertion andremoval of a work-piece, and means for restricting the gyratory movement of the spindle to an area which will allow its point to automatically engage the center in a workpielcte when the latter is resting upon the sup- P 10. A machine of the character described, including opposed grinding-and regulating wheels and an intermediate work-support,

. and means for controlling the position of a stricting the gyratory movement of the spindle'to an area whichwill allow its point to automatically engage the center in a workpiece when the latter is resting upon the support, and additional means for restricting the movement of the spindle and work-piece carried thereby, in the direction of the operative face of the grinding wheel.

11. A machine'of the character described,

. A including opposed grinding and regulating wheels and an intermediate work-support, and means for controlling the position of a work-piece on the support, including centering spindles,.'one at least of said spindles being mounted for gyratory movement about a point remote from its work-engaging end,

and one of said spindles being longitudinally movable relative to the otherfor insertion and removal of a work-piece, means for restricting the gyratory movement of the spindle to an area which will allow itspoint to automatically engage the center in aworkpiece when the latter is resting upon the su port, additional means for restricting 't a movement of thespindle and work-piece car--.

ried thereby, in the direction of'the operative face of the grinding wheel, said means including a stop member having a receding surface as respects the grinding wheel, whereby as the diameter of the work decreases, the axis ghereof will advance toward the grinding surace.

12. A grinding machine for the production of cylindrical work including opposed grind ing and regulating wheels, and an intermediate work-rest for rotatably supporting work during the operation of the wheels thereon, and means for establishing a predetermined axis for the work-piece during grinding thereof.

13. A grinding machine including opposed grinding and regulating wheels forming a work-receiving throat therebetween, a pair of centering spindles carried by-the machine in alinement with the throat'for engagement with a workpiece in grinding osition within the throat, and a vertically a justable workrest carried by the machine and projecting between the wheels, whereby said rest may be adjusted to peripherally engage and support a workpiece when held between the centering spindles within the throat.

14. A grinding machine including opposed grinding and regulating wheels forming a work-receiving throat therebetween, a pair 0t centering spindles carried by the machine in alinement with the throat for engagement with a work-piece in grinding position within the throat, and a vertically adjustable workrest carried by the machine and projecting between the wheels, whereby said rest may be adjusted to peripherally engage and support a work-piece when held between the centering spindles within the threat, at least one of said spindles being axially movable for engagement and disengagement of the workpiece.

15. A grinding machine including opposed grinding and regulating wheels forming-a work-receiving throat therebetween, a air of centering spindles carried by the mac ine in alinement with the throat for engagement with a work-piece in grinding position within the throat, and a vertically adjustable work-rest vcarried by the machine and proj ecting between the wheels, whereby said rest may be adjusted to peripherally engage and support a work-piece when held between the centering spindles within the throat, at least one of said spindles being axially movable for engagement and disenga ement of the workpiece; and at least one 0 said spindles being movable in a direction toward the plane of the operative face of the grinding wheel.

16. A grinding machine including opposed grinding and regulating wheels forming a work-receiving throat thercbetween, a pair of centering spindles carried by the machine in alinement with the throat for engagement with a workpiece in grinding position within the throat, and a vertically adjustable workrest carried by the machine and projecting between the wheels, whereby said rest may be adjusted to peripherally engage and support a work-piece when held between the centering spindles within the throat, at least one of said spindles being axially movable for engagement and disengagement of the workpiece and at least one of said spindles being movable in a direction toward the plane of the operative surface of the grinding wheel, and a receding stop mechanism for limiting the movement of the spindle in said direction. 17. in a machine of the character de: scribed, a work-engaging member comprising a spindle, having a point for engagement in a work-center, means supporting the spindle for universal gyratory movement, a guidebracket independent of the supporting means for the spindle, having a passage loosely sup porting the same to limit the gyratory movement thereof.

18. in a machine of the character described, a work-engaging member comprising a spindle having a point for engagement in a work-center, means supporting the spindle for universal gyratoryniovement, a guide bracket for the spindle, having a passage loosely supporting the same to limit the gyratory movement thereof, and means for resiliently urging the spindle in one direction to facilitate the picking up of work thereby. 19. In a machine of the character described, a work-engaging member comprising a spindle, having a point for engagement in a work-center, means supporting the spindle for universal gyratory movement, a guide bracket for the spindle, having a passage loosely supporting the same to limit the gyratory movement thereof and adjustable means for limiting the movement of the spindle in one direction as respects its bracket.

20. In a machine of the character described, a work-supporting mechanism, in-

cluding a bracket having a passage, a block.

slidable within the passage, means for determining the position of theblock' within the supporting brackettherefore, a spindle having ball and socket connection with the block, and means forlimiting the universal movement of the spindle as respects the block.

21. In a machine of the character described, 'a work-supporting mechanism, including a bracket having a passage, a block slidable within the passage, means for determining'the position of the block within the supporting bracket therefor, a spindle having ball and socket connection with the block, means for limiting the universal movement of the spindle as respects the block, a supplemental bracket engag ing the spindle and port for and work engaging means for urgin a workpiece when between the centers in the direction of the grinding wheel.

23. A grinding machine including a bed, I

work-supporting spindles carried by the bed, a grinding wheel and regulating wheel disposed in opposition to each other and each independently adjustable with respect to the spindles, a work-support intermediate the grinding and regulating wheels and means for adjusting the work-support in the direction of the spindles and at an angle to the direction of the adjustment of the grinding and regulating wheels.

24. A grinding machine of the centerless type for production of articles of circular form in cross section, including a bed or support, a grinding wheel carried by the bed and rotatableat a high or grinding peripheral rate of'speed and with its inner face mov ing in the direction toward the support, a regulating wheel carried by the support in opposition to the grinding wheel and having its operative surface adjacent the grinding wheel moving in the opposite direction from the adjacent grinding wheel surface and at a slow. rate of speed to control the rate of rotation of a Work piece when in position between the wheels, a pair of work engaging centers carried by the support and laterally displaced as respects the throat between the grinding and regulating wheels, at least one of said centers being supported for free oscillatory movement in the direction toward and away from ,the grinding wheel, means for limiting the oscillatory movement in the direction of the axis of the grinding wheel, whereby the relative approach of the axis oi the workas determined by the centers and the axis of the grinding wheel may be definitely established, a bracket carried by the support, and a work rest member carried by the bracket andprojecting into the grinding throat between the grinding and regulating wheels for lateral engagement with a work piece, said work rest being mounted on the bracket for diagonal inward and upward adjustment as respects the centers 1n a plane radial to the axis determined by said centers, whereby said work rest may be brought into corresponding engagement with dili'erent diameters .of-work pieces.

25. A machine for the production of work to a prescribed axis comprising a work superipheral engagement with the portion oi work to be ground, a grlnding wheel disposed at one side of the work sup port and operable at a grinding rate of speed and in the direction of the work support to urge the work thereagainst, a regulating wheel disposed at the opposite side of the work support for engagement with the portion of work being ground, said regulating wheel being operable at a slow work controlling rate of speed and with its ogierative surface moving in a direction away rom the work rest, means for shifting one of said wheels to decrease the distance therebetween for reduction of work diameter, and means engaging the work to positively limit the relative axial approach, of work and grinding wheel. V a

26. A machine for the production of work to a prescribed axiscomprising a work support for peripheral engagement with the portion of work to be ground, a grinding wheel disposed at one side of the work support and operable at a grinding rate of speed and in the direction of the work support to urge the. work thereagainst, a regulating wheel disposed at the opposite side of the work support for engagement with the portion of work being ground, said regulating wheel being operable at a slowwork controlling rate of speed and with its operative surface movgin a direction away from the work rest, means for shifting one of said wheels to decrease the distanoe therebetween for reduction of work diameter, whereby a three point variable grinding throat is provided in which the work may float during the grinding operation, and means for terminally engaging the work to limit the movement of the predetermined axis thereof in the direction of the grinding wheel without restrain-t of its general floating movement on the supporting work rest.

27. A mechanism of the character described, including opposed grinding and regulating wheels forming a work-receiving throat therebetween, means within the throat forrengaging a portion of the periphery of the surface being ground at the moment and supporting a work piece against displacement relative to the wheels,

the work piece on its support in the direction of one ofthe wheels.

28. A' mechanism of the character described, including opposed grinding and.

regulating wheels forming a work-receiving regulating wheel disposed and means exterior -to the throat for-limiting the movement of throat therebetween, a work support disposed 7 within the throat, a plurality of means exteriorly of the throat and projecting into alignment therewith for positioning a work piece within the throat, means for adjustably varying the position of one of said work limiting means and additional means for shifting the'other of said work limiting means into and out of alignment with the throat.

30. A grinding machine of the character described, including a grinding wheel, a support disposed adjacent the grinding wheel for peripheral engagement with a rotary work piece and adapted to engage the surface of the work as the latter is being ground,

means in opposition to the grinding wheel for engagement with the surface of the work as it is being acted on to urge the work transversely of the support in the direction of the grinding wheel, and means exterior to the grinding wheel for engagement with projections on the work to limit the movement of the work axis in the direction of the grinding wheel.

31. In a precision grinding machine for producing concentric work pieces the com-.

bination of a bed, work supporting members carried by the bed, a grinding wheel and a in opposition to each other and independently adjustable with respect .to the work supporting members, a work support intermediate the grinding and regulating wheels and the above mentionedwork supporting members, and means for adjusting the last mentioned work support in a radial direction with respect to the axis of the work piece and work supporting members.

32. In a machine of the character described the combination of a bed, a grinding wheel carried thereby, a work supporting mechanism for presenting work to the grinding wheel, said work'supporting mechanism including a pair of centers terminally engaging the workfor initially positioning the same, means peripherally supporting the work for rotation while it is being ground, and means frictionally engaging the work for controlling the rotation thereof during grinding. I V

33. In a machine for grinding work pieces. concentric to a predetermined axis, the combination of a grinding wheel, a work supporting mechanism including centers for terminally engaging the work, means peripherally supporting the work while it is bein ground, and means including a member irictlonally engaging the work for controlling rotation thereof and a slide for urging the work into the grinding wheel for stock removal.

34. A machine. for grinding concentric workpieces or the like including a grinding wheel and a wo'rkholding fixture adjacent the grinding wheel, said fixture including means terminally engaging a work piece and means for laterally eng 'ng and supporting the body portion there di said body portion engaging means including a member frictionally engaging the said body portion for controlling the rotation thereof.

35; A machine for grinding concentric work pieces or the like, including a grinding wheel. and a Work holding fixture adjacent the grinding wheel, said fixture including means for terminally engaging a work piece, means for laterally engaging and supporting the body portion thereof, said body portion engaging means including a member for con trolling the rotation of the said body portion and means for moving the member into and out of engagement with the work piece to facilitate insertion and removal of the said work piece.

In witness whereof, I hereunto subscribe my name. A

JOHN E. QASTER. 

